In order to include an oily component transparently in an emulsion cosmetics, there is a method in which the oily component is solubilized in micelles formed by a surface active agent. However, since the amount of the oily component to be solubilized is extremely small, its effects in sufficiently exerting functions of the oily component and improving touch to the skin are not satisfactory.
Also known are micro-emulsion methods which use surface chemical properties of surface active agents, such as liquid crystal emulsification, D-phase emulsification and phase inversion emulsification, but these methods also have a limitation regarding the amount of oily component which can be involved transparently (JP-A-63-126542; the term “JP-A” as used herein means an “unexamined published Japanese patent application”). They also have other limitations, e.g. the kinds of surface active agents are limited because the surface chemical properties thereof are spoiled in some cases depending on the kinds of an oily component to be jointly used.
On the other hand, a high pressure emulsification method is known in which a refined emulsion having an average emulsion particle size of 0.2 μm or less is obtained by making use of a high pressure emulsifier (e.g., JP-A-63-126543, JP-A-4-48925).
The refined emulsion obtained by high pressure emulsification method generally has a low viscosity of between 10 and 100 mPa·s, so that its use is limited. Though a gelatinous emulsion which has relatively high viscosity can be applied to various cosmetics such as moisturizing lotion, body lotion and hair treatment, the refined emulsion cannot be used as such due to its low viscosity, so that there is a method to increase the viscosity using a water-soluble thickener. However, a product thickened with a thickener frequently becomes sticky just as it dries after its application, so that there is a great demand for an emulsion cosmetic which is transparent and high in viscosity and has good feeling in use.